Author Affiliations
Abstract
Key Laboratory of Radar Imaging and Microwave Photonics, Ministry of Education, Nanjing University of Aeronautics and Astronautics, Nanjing 210016, China
We demonstrate microwave photonic radar with post-bandwidth synthesis, which can realize target detection with ultra-high range resolution using relatively small-bandwidth radio frequency (RF) frontends. In the proposed radar, two temporal-overlapped linear frequency-modulated (LFM) signals with the same chirp rate and different center frequencies are transmitted. By post-processing the de-chirped echoes in the receiver, a signal equivalent to that de-chirped from an LFM signal with the combined bandwidth is achieved. In a proof-of-concept experiment, two LFM signals with bandwidths of 8.4 GHz are exploited to achieve radar detection with an equivalent bandwidth of 16 GHz, and a range resolution of 1 cm is obtained.
microwave photonics ultra-high resolution synthetic bandwidth Chinese Optics Letters
2020, 18(7): 072501
1 中国科学院长春光学精密机械与物理研究所, 吉林 长春 130031
2 中国科学院大学, 北京 100049
支撑结构是连接卫星与相机的关键部件, 在发射和在轨环绕阶段对相机提供保护和空间应用需求。深空探测器发射阶段的振动载荷高达13 g甚至更高(地球探测为8~9 g), 支撑结构既要克服剧烈振动可能造成的相机结构破坏还要保证光学系统的热稳定, 具有较高的设计难度。通过分析不同支座形式的结构特点设计了刚性支座、平动支座两种不同的支座形式, 从刚度和热稳定的均衡性出发将两种支座形式进行了组合设计, 提出了“一个刚性支座+两个平动支座”的设计方案。理论分析与实验验证得到: 该支撑结构的一阶频率为58 Hz, 远高于整星基础频率, 温降15 ℃仿真分析结果显示主镜偏转角为3.66″, 次镜及三镜相对主镜最大偏转角为7.85″, 均满足设计要求。振动及热平衡试验表明: 相机各项指标正常。
支撑结构 深空探测 遥感相机 平动支座 support structure deep space exploration remote sensing camera sliding foot 红外与激光工程
2018, 47(6): 0618004
